I begin to consider you don't speak german, so let me take you through it step by step:
Its about this:
(1) Wer eine Person unter achtzehn Jahren dadurch missbraucht, dass er unter Ausnutzung einer Zwangslage sexuelle Handlungen an ihr vornimmt oder an sich von ihr vornehmen
It's illegal to use a situation of pressure (for the lack of a literal translation of Zwangslage) to conduct sexual intercourse with a person under 18!
True, you didn't came to the intercourse, but this is where point 4 comes in:
(4) Der Versuch ist strafbar.
Trying is illegal.
So, 16, and you not scoring doesn't matter shit. The only question is if she was in a spot of pressure, and that's something that very much depends on her, not on you - and according to what she texted you, it was definitely not a pleasant experience. Also you admitted to luring. In my opinion this is an easy case.
Edit, just in case you consider me making this up:
https://www.gesetze-im-internet.de/stgb/__182.html